"Periods of rain and snow" are expected across Long Island and the city into this evening, according to an earlier weather service statement, and any accumulations will be "mainly on grassy and elevated surfaces."

Most of that accumulation will be a slushy coating of wet snow, the statement said.

The most intense precipitation was expected from early afternoon through the evening commute, winding down in the late evening to early Wednesday morning, Picca said. Roads may be slick, and drivers are advised to "take their time on the way home," he said.

At LaGuardia Airport, meanwhile, the weather was causing delays averaging 1 hour and 14 minutes on some arriving flights Tuesday afternoon, with arrival delays averaging 1 hour and 39 minutes at Newark Liberty, according to the Federal Aviation Administration. Some departures were also being delayed, and the FAA advised travelers to check with their airlines.

Also, Wednesday could loom as a problem commute -- with overnight temperatures expected to dip below freezing, leading to the potential for hazardous black ice conditions.

Cold temperatures are in the offing in the aftermath of the system, as well, weather service meteorologist Tim Morrin said.

The weather service said temperatures are expected to run about 8 degrees below normal for the remainder of the week -- that is, with highs in the low 40s and lows in the mid- to high 20s. Forecasters believe the average temperature for November will be about 3 or 4 degrees below normal, Morrin said, after a long run of above-normal temperatures on Long Island. But, Morrin said, the below-normal average temperatures will likely not be record-breaking.